Monoazo dye.



UNITED STATES Patented May 12, 1903.

PATENT OFFICE.

MYRTIL KAHN, OF ELBERFELD, GERMANY, ASSIGNOR TO FARBENFA- BRIKEN OF ELBERFELD 00., OF NEW YORK, N. Y., A CORPORATION OF NEW YORK;

MONOAZO DYE.

SPECIFICATION forming part of Letters Patent No. 727,966, dated May 12, 1903.

Application filed February 25, 1903. Serial No. 145,080. (No specimens.)

To all whont it may concern.-

Be it known that I, MYRTIL KAHN, doctor of philosophy, chemist, residing at Elberfeld, Germany, (assignor to the FARBENFABRIKEN OF ELBERFELD 00., of New York,) have in vented a new and useful Improvement in Monoazo Dyestufis and I do hereby declare the following to be an exact and clear description of my invention.

My invention relates to the production of new and valuable azo dyestufis by combining the diazo compounds of ortho-amidophenolsulfonic acids having the general formula:

one) N m) 6 2 soar x (X meaning a hydrogen atom which can be replaced by halogens, -NO,, SO H, or 0H, such as ortho-amidophenol-sulfonic acids, ortho-amidocresol-sulfonic acids, ortho-amidophenol-nitro-sulfonic acids, ortho-amidophenol-chloro-sulfonic acids, ortho-amidophenoldisulfonic acids, or the like, with 1:7-amid0- naphtholl-sulfonic acid having the formula:

som

The new azo dyestuffs thus obtained are brownish-black powders soluble in water with from a reddish-violet to bluish-violet color, turning blue on adding a solution of sodium carbonate, and dyeing wool from acid-bath from bluish-red to blue shades, turning black by a subsequent treatment with chromium compounds reacting as oxidizing agents. The black shades thus obtained possess a great fastness to the potting process, which is a finishing process for woolen piece goods. In this process the goods are entered into boiling Water and allowed to remain there until the water is cold. The goods thus assume a high degree of gloss and softness, and according to the effect desired the potting may be repeated several times.

In carrying out my process practically I can proceed as follows, the parts being by weight: 23.5 parts of ortho-nitro-ortho-amidophenolpara-sulfonic acid having the formula:

SOLE are diazotized in the usual manner, and the resulting diazo compound is stirred into a solution of twenty-four parts of 1 :7-amidonaphthol-i-sulfonic acid in an excess of causticsoda lye. After being stirred for some time the excess of caustic-soda lye is neutralized by means of hydrochloric acid, and the new dyestuff is precipitated by the addition of common salt, filtered OE, and dried.

The new coloring-matter thus obtained is in the shape of the sodium salt when dry and pulverized, a brownish-black powder soluble in water to a bluish-violet solution and soluble in concentrated sulfuric acid of 66 Baum with a red color, which is changed to yellowish red on adding a small quantity of ice, a yellowish-red precipitate being obtained by the addition of a larger quantity of ice. It dyes wool from acid-bath blue shades. By subsequently treating the dyed fiber with chromium compounds reacting as oxidizing agents-such as chromates, bichromates, or the like-the shades are changed to black, distinguished for great fastness to the potting process. They also resist milling and washing and possess a great fastness against the action of light.

Having now described my invention, What I claim is- 1. The herein-described new azo dyestuifs derived from ortho-amidophenol derivatives having the above-given formula and 1 :7-amidonaphthol- I-sulfonic acid, which, when in a dry state, are brownish-black powders soluble in water with from a reddish-violet to blu ish-violet color turning blue on adding a solution of sodium carbonate and dyeing wool from acid-bath from bluish-red to blue shades yellowish-red precipitate being obtained by addition of a larger quantity of ice; dyeing wool from acid-bath blue shades which are changed to black by a subsequent treatment with chromium compounds reacting as oxidizing agents, substantially as described.

In testimony whereof I have signed my name in the presence of two subscribing witnesses.

MYRTIL KAHN.

Witnesses:

OTTO KoNIG, J. A. RITTERsHAUs. 

